GPU command decoder uses depth24_stencil8_oes extension if available.

This is now the only depth / stencil format supported by ANGLE. Other GLES2 implementations will only use it if the extension is supported.

Also changed all usage of GLES2_GPU_SERVICE_BACKEND_NATIVE_GLES2 to a runtime check since we no longer know at compile time whether the backend will be GL ot GLES2.

TEST=try, GPU unit tests locally, WebGL locally, Pepper 3D locally
BUG=none

Review URL: http://codereview.chromium.org/3046035

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@54627 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 21 insertions, 0 deletions

diff --git a/app/gfx/gl/gl_context.cc b/app/gfx/gl/gl_context.cc
index d9b81f3..1d79072 100644
--- a/app/gfx/gl/gl_context.cc
+++ b/app/gfx/gl/gl_context.cc
@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+#include <string>
+
 #include "app/gfx/gl/gl_context.h"
 #include "app/gfx/gl/gl_bindings.h"
 #include "app/gfx/gl/gl_implementation.h"
@@ -9,6 +11,19 @@
 
 namespace gfx {
 
+bool GLContext::HasExtension(const char* name) {
+  DCHECK(IsCurrent());
+
+  std::string extensions(reinterpret_cast<const char*>(
+      glGetString(GL_EXTENSIONS)));
+  extensions += " ";
+
+  std::string delimited_name(name);
+  delimited_name += " ";
+
+  return extensions.find(delimited_name) != std::string::npos;
+}
+
 bool GLContext::InitializeCommon() {
   if (!MakeCurrent())
     return false;
@@ -19,4 +34,5 @@ bool GLContext::InitializeCommon() {
 
   return true;
 }
+
 }  // namespace gfx
diff --git a/app/gfx/gl/gl_context.h b/app/gfx/gl/gl_context.h
index e14e7460..656a0d3 100644
--- a/app/gfx/gl/gl_context.h
+++ b/app/gfx/gl/gl_context.h
@@ -41,6 +41,10 @@ class GLContext {
   // Get the underlying platform specific GL context "handle".
   virtual void* GetHandle() = 0;
 
+  // Returns whether the current context supports the named extension. The
+  // context must be current.
+  virtual bool HasExtension(const char* name);
+
   static bool InitializeOneOff();
 
 #if !defined(OS_MACOSX)
diff --git a/app/gfx/gl/gl_context_stub.h b/app/gfx/gl/gl_context_stub.h
index 222bf7b..b5189ae 100644
--- a/app/gfx/gl/gl_context_stub.h
+++ b/app/gfx/gl/gl_context_stub.h
@@ -23,6 +23,7 @@ class StubGLContext : public gfx::GLContext {
   virtual void SwapBuffers() {}
   virtual gfx::Size GetSize() { return size_; }
   virtual void* GetHandle() { return NULL; }
+  virtual bool HasExtension(const char* name) { return false; }
 
   void SetSize(const gfx::Size& size) { size_ = size; }